Table 3. Presurgical versus  Postsurgical Intravenous and Intramuscular NMDA Receptor Antagonists

NMDA =N -methyl-d-aspartate; NS = no significant difference between treatment groups or no significant difference in favor of the preemptive treatment;P < 0.05 = significant difference between treatment groups in favor of the preemptive treatment; —= not evaluated; PCA = patient-controlled analgesia; VAS = visual analog scale.